The present invention relates to a work helmet having a transmitter-receiver which is used for effecting an intercommunication between workers who are engaged in various works such as inspection examination and repair inside a specific construction.
Among various kinds of known work helmets for workers who work in a construction such as underground substation, underground market and building, there has been proposed a work helmet having a wireless communication device installed therein for carrying out an intercommunication between workers and sometimes between a central control room and respective workers. To this end, a conductor serving as an antenna is usually extended between the control room and various places inside the construction so as to transmit information in the form of the electromagnetic wave between the helmet and conductor. However, the electromagnetic wave is liable to be affected by interference and therefore the information signal having a high S/N could not be obtained.
In addition, the known work helmet with the wireless communication device is not sufficiently useful for effecting emergency intercommunication between the central control room and respective workers upon the occurrence of disaster such as fire. This is due to the fact that in the known work helmet as long as the worker wearing the helmet does not send his message to the control room, the control room could not know his position and even his existence in the construction. Therefore, it is not possible to inform the worker of any guide information adequate for the emergency escape upon the disaster. Furthermore, in order to transmit from the control room to respective workers much more useful information, it is preferable that the control room can identify respective workers as well as positions or sections in the construction of particular workers. For instance, if the control room can grasp the position at which a worker situates without receiving any message from him, the control room will be able to send the most adequate message to him.